Biomedical subjects

Shun Wada

Publications and source records attributed to Shun Wada.

7 recordsLinked to original sources

PubMed2005

Direct methylation from mouse plasma and from liver and brain homogenates.

The analysis of fatty acid composition of plasma and tissue is important as a method for studying lipid nutrition. We investigated the possibility of direct methylation of fatty acids by BF(3)-methanol from plasma and from liver and brain homogenates without lipid extraction. There were no ghost peaks in the chromatogram produced by the direct methylation method. The 18:0 percentages were significantly higher in the direct methylation method than in the lipid extraction method. There were not remarkable differences in fatty acid composition in the direct methylation and methylation after lyophilization methods. Furthermore, the recovery ratio of the internal standard in the direct methylation method was higher than that in the lipid extraction method. The difference of fatty acid composition with lipid extraction may be caused by the change of lipid class extraction. Therefore, the direct methylation method without lipid extraction is the most suitable for determining fatty acid composition in plasma and tissue.

Animals↗

PubMed2003

Phenolics composition and antioxidant activity of sweet basil (Ocimum basilicum L.).

The antioxidant activity of a methanolic extract of Ocimum basilicum L. (sweet basil) was examined using different in vitro assay model systems. The crude extract was fractionated on a Sephadex LH-20 column, and six fractions were identified. The DPPH scavenging assay system and the oxidation of the soy phosphotidylcholin liposome model system were used to evaluate the antioxidant activity of each fraction. Fraction IV showed the strongest activity followed by fractions V and VI. Phenolic compounds responsible for the antioxidative activity of the fractions were characterized by atmospheric pressure chemical ionization liquid chromatography-mass spectrometry. The major antioxidant compound in fraction IV was confirmed as rosmarinic acid by (1)H NMR and characteristic fragmentations in the mass spectrum. Moreover, the native of antioxidant activity of rosmarinic acid in the liposome system was examined. The results showed that one rosmarinic acid can capture 1.52 radicals, and furthermore, the existence of a synergistic effect between alpha-tocopherol and rosmarinic acid was revealed.

Antioxidants↗

PubMed2003

Variation in lipid classes and fatty acid composition of salmon shark (Lamna ditropis) liver with season and gender.

The influence of season and gender on lipid content, lipid classes, and fatty acid compositions was assessed in livers of salmon shark (Lamna ditropis), caught in the Pacific Ocean. No significant difference in the hepatosomatic index was noted with season, though the lipid content was significantly higher (P<0.05) in winter. Triacylglycerol (TAG) was identified as the predominant lipid class (78.5-82.0%), followed by sterol esters (5.7-9.1%) and hydrocarbons (3.4-5.4%). No significant differences were observed in TAG composition with respect to the season or gender. However, diacylglyceryl ether contents were significantly higher (P<0.05) in winter (3.8-5.3%) than those obtained in summer (1.3-1.1%). Polyunsaturated fatty acids constituted the major fatty acid class of salmon shark total liver lipid and docosahexaenoic acid (C22:6n-3) (22.7-28.4%) was the most abundant fatty acid which was significantly lower (P<0.05) in winter. These results suggested that lipid characteristics of salmon shark liver were influenced by season, but not by gender.

Animals↗

PubMed2002

Method for analysis of 4-hydroxy-2-(E)-nonenal with solid-phase microextraction.

A simple analytical method for 4-hydroxy-2-(E)-nonenal (HNE) using solid-phase microextraction (SPME) fiber was developed. HNE or the derivative of HNE formed by reaction with 2,4-dinitrophenylhydrazine (DNPH) was extracted from the sample solution by immersing the SPME fiber into the solution, and the amount of HNE was quantified by HPLC. The extraction conditions of HNE and HNE-DNPH were examined, using standard solutions, with respect to fiber coating, NaCl concentration, rate of stirring, adsorption temperature, and adsorption time. The recovery of HNE reached 80%, and the quantification limits of HNE and HNE-DNPH using standard compounds were 14.1 pmol/10 mL and 486.5 fmol/10 mL, respectively. This method can be applied to the detection of HNE in oxidized oil or samples of porcine liver.

Aldehydes↗

PubMed2002

Dietary and seasonal effects on the dorsal meat lipid composition of Japanese (Silurus asotus) and Thai catfish (Clarias macrocephalus and hybrid Clarias macrocephalus and Clarias galipinus).

The effects of dietary lipids and seasonal variation on the lipids of wild and cultured catfish (Japanese catfish, Silurus asotus; Thai catfish, Clarias macrocephalus and hybrid Clarias macrocephalus x Clarias galipinus) were determined by analysis of the lipid content and fatty acid composition of their dorsal meat. The predominant fatty acids of dorsal meat were 16:0, 18:1n-9, 18:2n-6, 20:4n-6 (arachidonic acid, AA), and 22:6n-3 (docosahexaenoic acid, DHA). The DHA content in the diet of Japanese catfish was higher than that in the diet of Thai catfish, and this was reflected in the dorsal meat of the Japanese catfish, which had a remarkably high percentage of DHA compared with the meat of the Thai catfish. Cultured Japanese catfish had a higher percentage of 18:2n-6 than Thai fish and a lower percentage of AA in winter than in summer season. There were also seasonal variations in the percentage of n-6 fatty acids in Japanese catfish. In summer, the fatty acid composition of the cultured Japanese catfish was similar to that of the wild catfish. These fatty acid changes in the lipid classes, triacylglycerol, phosphatidylcholine and phosphatidylethanolamine were similar to those observed for total lipids. These results indicate that the percentage of DHA in the dorsal meat of catfish is influenced by dietary fatty acid, and it may be that it can be increased in cultivated fish by administering a diet containing a large amount of DHA.

Animals↗

PubMed2002

Optimization of heterotrophic culture conditions for n-alkane utilization and phylogenetic position based on the 18S rDNA sequence of a thermotolerant Prototheca zopfii strain.

This study reports on the optimization of the culture conditions for a thermotolerant eukaryotic algal strain, Prototheca zopfii RND16, which can effectively degrade and assimilate n-alkanes at elevated temperatures. RND16 was able to grow on 1% (v/v) n-alkanes (C14-C17) at temperatures up to 38 degrees C. This ability differs from a previous finding that P. zopfii did not grow on hydrocarbons under temperature conditions above 25 degrees C. Increasing the temperature from 25 degrees C to 30-35 degrees C resulted in an increase in the rate of n-alkanes consumption during growth of RND16 in quiescent culture. In shaking culture at 35 degrees C, RND16 removed a 1% n-alkanes mixture almost completely at the basal medium salinity within 8 d. However, an appreciable decrease in the extent of hydrocarbon utilization was observed with increasing salinity and substrate concentration in the medium. The slow consumption of the n-alkanes in the early stage of degradation at 25 degrees C was improved by supplementing 0.1% glucose. A comparative study on the nuclear small subunit rDNA (18S rDNA) sequences of three strains within the genus Prototheca revealed that both P. zopfii ATCC 30253, which utilize n-alkanes at room temperature and P. moriformis ATCC 50081, which does not assimilate n-alkanes, are closely related to RND16.

Journal Article↗

PubMedDate not supplied

Determination of docosahexaenoic acid and n-3 fatty acids in refined fish oils by 1H-NMR spectroscopy: IUPAC interlaboratory study.

A high-resolution proton nuclear magnetic resonance (NMR) method for determining the concentration (mg/g) of docosahexaenoic acid (DHA), the molar proportion (mol%) of DHA, and the molar proportion of total n-3 fatty acids in fish oils was validated by an IUPAC interlaboratory study (the Commission VI-6 on Oils, Fats, and Derivatives WG 3/98). Thirteen laboratories from 5 countries tested 6 pairs of blind duplicate fish oils: a refined tuna oil, 2 extracted tuna oils, an extracted bonito oil, an extracted salmon oil, and an extracted sardine oil ranging from 9 to 30 mol% DHA and from 20 to 35 mol% n-3 fatty acids. Before 1 D-proton NMR measurements with 300-500 MHz instruments, oil samples were weighed and diluted with deuterochloroform solution containing ethylene glycol dimethyl ether as internal standard. To achieve precise performance, a detailed procedure for signal area measurement was described in the protocol, and all participants were instructed about the critical importance of following the protocol. Statistical performances with invalid and outlier data removed were as follows: repeatability relative standard deviations (RSDr) ranged from 0.91 to 2.62% and reproducibility relative standard deviation (RSDR) ranged from 1.73 to 4.27% for DHA concentration (mg/g); RSDr ranged from 0.39 to 2.06%, and RSDR ranged from 0.59 to 3.46% for mol% DHA; RSDr ranged from 0.23 to 0.90% and RSDR ranged from 0.85 to 2.01 % for mol% total n-3 fatty acids. The method is expected to be recommended by IUPAC.

Docosahexaenoic Acids↗